The present invention relates to electrical connectors and interconnect devices and to methods therefor and, more particularly, to maintenance of signal isolation and integrity and obtaining high signal density in connectors and connector systems used in association with printed circuit boards, circuit cards, back panels and other like substrates.
Advancing technology has allowed the development of high density electronic circuits and components located on printed wiring boards and printed circuit boards. This miniaturization of electronic circuits and components has created a need for electrical connectors to interconnect electrically and mechanically one printed circuit board, such as a back panel or mother board, to one or more other printed circuit boards, such as daughter boards. To retain the benefits of this miniaturization, it is desirable for the connectors to have high signal densities. For example, it is desirable for there to be a large number of signals per unit space, such as surface area or volume of the connectors. However, high signal density in a connector can lead to electrical interference and cross-talk, where the signal in one signal conductor of a connector causes degradation in the signal of an adjacent signal conductor. Accordingly, there is a need to reduce such interference, cross-talk and similar signal degradation, and especially to do so in relatively small size connectors while providing relatively high signal density.
In addition, technological advances have led to higher switching speeds in printed circuit boards. As switching speeds increase, signal integrity becomes all the more important. Signal propagation speed also takes on increased importance as switching speeds increase. Higher signal propagation speeds and miniaturization also tend to increase signal reflections along conductive paths, and this is another source of signal degradation. Accordingly, there is a need to provide for relatively high signal propagation speeds with relatively low reflection.
Shields and ground conductors have been used in the past to reduce cross-talk and other signal degradation in electrical connectors and in cables. The ground conductors and/or shields were coupled to actual ground reference potential or to some other reference potential (hereinafter the term xe2x80x9cgroundxe2x80x9d also means a source of reference potential, whether an actual ground or some other potential) and they were held in place in relation to the signal conductors by the connector housing, for example, resulting in a relatively large and complex device that is relatively difficult and/or costly to manufacture. Accordingly, there is a need to minimize the complexity of connectors and to facilitate manufacturing, and, accordingly, to minimize cost of connectors.
From the foregoing, it can be seen that there is a need for electrical connectors that minimize electrical interference or cross talk and maximize signal density, while maintaining manufacturability.
Briefly, the present invention concerns an electrical connector system (sometimes referred to as an interconnect system) that allows high signal density with means of electrical isolation to minimize degradation of electrical signals.
According to an aspect of the invention, an electrical interconnect system includes two connector portions, each for connection to a respective circuit board or the like and for interconnection with each other thereby to interconnect the circuit boards or the like.
According to another aspect of the invention, an electrical interconnect system includes signal conductors which are surrounded by multiple reference or ground conductors. In an embodiment of the invention, a given signal conductor may be surrounded by four reference conductors.
According to still another aspect of the invention, an interconnect system includes a reference element with two sets of reference conductors, one of the sets offset a distance from the other set.
To the accomplishment of the foregoing and related ends, the invention comprises the features hereinafter fully described and particularly pointed out in the claims. The following description and the annexed drawings set forth in detail certain illustrative embodiments of the invention. These embodiments are indicative, however, of but a few of the various ways in which the principles of the invention may be employed. Other objects, advantages and novel features of the invention will become apparent from the following detailed description of the invention when considered in conjunction with the drawings.